Systems and strategies for expanding and enhancing an operator's awareness of a machine environment have become commonplace in recent years. Prescribed location and configuration of operator cab structures, mirrors and, increasingly, electronic sensors and imaging devices are all used to improve operator and machine efficiency as well as operator awareness of obstructions and hazards.
A conventional imaging and display system typically positions an imaging device such as a digital camera at a fixed location on a machine, and produces a digital feed of the field of view of the camera. Such cameras may have a fixed field of view, or in some instances a field of view that can be adjusted by rotating the camera upon a mount. The operator can view the images produced by the camera on a display positioned within the operator cab in a well-known manner.
A shortcoming in conventional strategies is that the camera commonly has a limited field of view that includes only a portion of what the operator would ideally be provided. Cameras positioned upon movable mounts and the like can partially address such limitations, but tend to be more expensive and less reliable. In recent years, proposals have been made to utilize multiple cameras to provide an operator multiple or composite images that encompass most or all of the surrounding machine environment.
A challenge arising in the context of synthesizing multiple different camera views is presentation of the image(s) to the operator in a way that accurately reflects the machine environment, but is also readily interpretable. Strategies for “taping” or “stitching” images are known which generally attempt to merge multiple different camera images into a realistic whole for displaying to the operator. U.S. Pat. No. 9,262,801 to MacMillan et al. is directed to one such strategy, and proposes multiple cameras arranged in an array that allows the cameras to have adjacent fields of view while each being pointed inward. The read window of an image sensor of each camera can allegedly be adjusted to minimize the overlap between adjacent fields of view, maximize correlation within the overlapping portions of the fields of view, and correct for manufacturing and assembly tolerances.